Computer-Assisted Compared with Conventional Total Knee Replacement: A Multicenter Parallel-Group Randomized Controlled Trial

Navigated and Robotic Total Knee Arthroplasty Do Not Confer Improved 5-Year Survivorship Compared to Conventional Total Knee Arthroplasty: An Analysis From the American Joint Replacement Registry

BACKGROUND

Computer-assisted navigation and/or the use of robotics at the time of the primary total knee arthroplasty (TKA) have been shown to improve implant position, minimize alignment outliers, and possibly improve patient outcomes compared to conventional instrumentation. The purpose of this study was to use the linked Medicare dataset from the American Joint Replacement Registry to compare the midterm (5-year) outcomes of navigated TKA and robotic TKA to those of conventional TKA.

METHODS

All primary TKA procedures submitted to the American Joint Replacement Registry between January 2017 and December 2022 among patients aged 65 years and older were included in the analysis. The data were stratified into patients who underwent navigated TKA, robotic TKA, or conventional TKA at the time of their index procedure. The all-cause revision rate, mechanical loosening rate, and the other mechanical complication rate were determined at five years postoperatively. The survival model was adjusted for age, sex, fixation type, and year.

RESULTS

At five years postoperatively, the survival model found computer navigation use to not be significant in TKA all-cause revision (P = 0.32) or mechanical loosening (P = 0.91), but was significant for other mechanical complications (P = 0.004). Robotic use was not found to be significant in TKA all-cause revision (P = 0.75), mechanical loosening (P = 0.42), or other mechanical complications (P = 0.46).

CONCLUSIONS

Navigation and/or the use of robotics at the time of primary TKA did not demonstrate a decrease in the need for revision at five years follow-up among Medicare beneficiaries. Although this study was unable to assess other important clinical outcomes following TKA with advanced technology, the purported benefits of using this technology to improve component survival are not supported.

Trends in adoption of robotics in arthroplasty: an analysis of the Indian landscape

Robotic-assisted technology in total joint arthroplasty (TJA) offers improved precision in component placement and alignment, addressing challenges, such as ligament imbalance, malalignment, and patient dissatisfaction. In India, where diverse healthcare settings exist, trends in robotic adoption remain underexplored. This study examines the adoption patterns and geographic distribution of robotic systems for TJA in India, highlighting market dynamics over the past 5 years. A cross-sectional observational study was conducted using data from manufacturers of robotic arthroplasty systems. Annual installations, tier-wise city classifications, and geographic distributions were analyzed. Statistical methods included descriptive analysis for installation trends, time-series visualization for adoption trajectories, and linear regression to forecast 2025 installations. As of September 2024, 290 robotic systems were installed across India. Among these, the CUVIS system (Meril) accounted for 89 installations (30.7%), followed by CORI (Smith and Nephew) with 66 installations (22.8%), and VELYS (DePuy) with 52 installations (17.9%). The MAKO system (Stryker) contributed 38 installations (13.1%), while MISSO (Meril) and ROSA (Zimmer) had 25 (8.6%) and 20 (6.9%) installations, respectively. Tier I hospitals dominated with 50% of installations, while Tier III and IV facilities accounted for only 10%. Linear regression predicts steady growth, with over 80 new robotic installations in 2025. Robotic technology adoption in Indian TJA has surged, with a strong preference for systems offering precision and versatility. However, barriers such as high costs and limited training impede penetration in lower tier facilities. Addressing these challenges could enhance equitable access and support the integration of robotics into diverse healthcare settings.

Accelerometer-Navigated Revision Total Knee Arthroplasty: A Technique for Successful Gap Balancing

Accelerometer-based navigation (OrthAlign) is the first computer-assisted surgical navigation system approved for use in the setting of revision total knee arthroplasty (TKA) in the United States. The senior author has used this technology in the revision setting for several years and developed the individualized, reproducible technique. The 4 goals during revision TKA are to (1) gain adequate exposure for the safe explanation of prior implants, (2) address any resultant bone loss, (3) restore the joint line via distal femur metal augmentation, and (4) ensure adequate stability through gap-balancing techniques and increasing the constraint of the revision implants as needed. This technique guide illustrates how accelerometer-based navigation (OrthAlign) can achieve these goals in the revision TKA setting.

Soft-tissue sound-speed-aware ultrasound-CT registration method for computer-assisted orthopedic surgery

Ultrasound (US) has been introduced to computer-assisted orthopedic surgery for bone registration owing to its advantages of nonionizing radiation, low cost, and noninvasiveness. However, the registration accuracy is limited by US image distortion caused by variations in the acoustic properties of soft tissues. This paper proposes a soft-tissue sound-speed-aware registration method to overcome the above challenge. First, the feature enhancement strategy of multi-channel overlay is proposed for U2-net to improve bone segmentation performance. Secondly, the sound speed of soft tissue is estimated by simulating the bone surface distance map for the update of US-derived points. Finally, an iterative registration strategy is adopted to optimize the registration result. A phantom experiment was conducted using different registration methods for the femur and tibia/fibula. The fiducial registration error (femur, 0.98 ± 0.08 mm (mean ± SD); tibia/fibula, 1.29 ± 0.19 mm) and the target registration error (less than 2.11 mm) showed the high accuracy of the proposed method. The experimental results suggest that the proposed method can be integrated into navigation systems that provide surgeons with accurate 3D navigation information.

Total knee replacement with an accelerometer-based, hand-held navigation system improves knee alignment: reliable in all patients

BACKGROUND

Achieving adequate alignment has traditionally been an important goal in total knee arthroplasty to achieve long-term implant survival. While accelerometer-based hand-held navigation systems (ABN) has been introduced as a way to achieve alignment, there is a limited body of evidence on its accuracy, especially in patients under 65 years with differing etiologies for knee arthritis. This study aimed to assess the precision of a specific ABN system in restoring the mechanical axis and report surgical variables and complications, with particular attention to younger patients.

METHODS

We conducted a retrospective review of 310 primary TKA performed with ABN from May 2016 to February 2021. The mean patient age was 67.4 (SD 8.9) years, with 43% under 65 years and mean body mass index of 33.2 (SD 6.8). The average surgical time was 96.8 min (57-171) and the average follow-up was 3.3 years (1.9-6.7). Data regarding length of stay, pain, range of motion (ROM), complications, and reinterventions were collected from the institutional joint arthroplasty registry and the medical records. Preoperative mechanical axis measurements and postoperative radiological data, including mechanical axis, component alignment and mechanical alignment outliers were analyzed.

RESULTS

The mean preoperative mechanical axis was 175.4° (SD 7.6), with 248 knees (80%) in preoperative varus. The mean postoperative mechanical axis was 179.5° (SD 1.96) with 98% of knees falling within ± 3° of the neutral mechanical axis. Only 6 knees (2 varus, 4 valgus) fell outside the ± 3° range. And 3 knees (1 varus, 2 valgus) fell outside the ± 5° range. In the sagittal plane, 296 knees (95.5%) knees were within ± 3° of goal of 3 degrees of femoral flexion and 302 (97.4%) knees were within ± 2° of goal 1° of slope for tibial component. Far outliers (alignment outside ± 5° of targeted position) were found in 3 knees. Factors such as posttraumatic arthrosis, previous surgery, presence of retained hardware, and age below 65 years were not associated with increase in alignment outliers and far outliers. No complications related to the navigation system were observed. There were 22 complications and 20 reoperations, including 2 revisions for periprosthetic joint infection and 1 revision for flexion instability. Patients that required knee manipulation achieved an ultimate flexion of 110° (SD 14.1).

CONCLUSIONS

The ABN system proved to be user-friendly and accurate in reducing alignment outliers in both coronal and sagittal planes in all patient populations. It offers a straightforward navigation solution while preserving surgeon autonomy and the use of traditional surgical tools. These findings advocate for the integration of this navigation system as a valuable tool to enhance the precision of TKA surgery in all patient groups.

Cemented vs Cementless Robotic-Assisted Total Knee Arthroplasty Yield Similar Short-Term Clinical Outcomes

Background

In primary total knee arthroplasty (TKA), there is ongoing controversy about optimal fixation (cemented vs cementless). Cemented TKA remains the gold standard, with the largest body of long-term evidence available to support it. However, cementless TKA implants are gaining popularity due to potential biomechanical advantages and a growing body of literature supporting survivorship. Due to paucity of literature investigating fixation methods in robotic-assisted TKA (Ra-TKA), we aim to compare clinical outcomes of cementless Ra-TKA with those of cemented Ra-TKA.

Methods

This is a retrospective cohort study of patients who underwent Ra-TKA by 19 surgeons comparing results of cases using cementless vs cemented fixation. We observed short-term complications, emergency room visits, and readmissions. We collected patient-reported outcomes measurement information system and knee injury and osteoarthritis outcome scores preoperatively and 12 weeks after surgery.

Results

A total of 582 TKA cases were included: 335 cementless and 247 cemented. The patients in the cementless group were younger and had a higher body mass index. The cemented group had a higher rate of return to the operating room, with manipulation under anesthesia for stiffness being the most common indication in both groups. There were no statistically significant differences in 30-day readmissions, 90-day emergency room visits, or patient-reported outcomes.

Conclusions

Our retrospective study demonstrated higher return to operating room in the cemented group vs the cementless group. We reported no differences in any other short-term outcomes between the cementless and cemented Ra-TKA. Our data support efficacy and safety of cementless Ra-TKA at 3-month follow-up.

Same-Day Total Joint Arthroplasty in the United States From 2016 to 2020: The Impact of the Medicare Inpatient Only List and the COVID-19 Pandemic

BACKGROUND

Same-day total hip arthroplasty (THA) and total knee arthroplasty (TKA) continue to gain popularity in the United States. The present study sought to quantify recent same-day outpatient trends taking into consideration the COVID-19 pandemic as well as the removal of these procedures from the Medicare inpatient only (IPO) list.

METHODS

Patients undergoing primary elective TKA and THA were identified using the Nationwide Ambulatory Surgery Sample and the National Inpatient Sample from January 1, 2016, to December 31, 2020. The same-day cohort included Nationwide Ambulatory Surgery Sample and National Inpatient Sample patients with a length of stay = 0 days. The inpatient cohort included patients with length of stay ≥1 day. National estimates were extrapolated using weight functions.

RESULTS

From January 2016 to December 2020, the proportion of same-day TKA increased from 1.2 (719) to 62.4% (31,293) and the proportion of same-day THA increased from 2.0 (599) to 54.5% (18,252). Following removal from the Medicare IPO list, same-day TKAs increased from 3.2% (1,895) in December 2017 to 13.8% (9,269) in January 2018, and same-day THAs increased from 10.7% (4,295) in December 2019 to 22.5% (8,708) in January 2020. Between February and March 2020, same-day TKAs increased from 42.4 (26,148) to 44.4% (16,972) and same-day THAs increased from 28.5 (10,729) to 30.2% (7,409).

CONCLUSIONS

The proportion of same-day TKA and THA dramatically increased following removal from the Medicare IPO list and in response to the COVID-19 pandemic. By December 2020, same-day TKA and THA accounted for >50% of all cases performed in the United States.

Exercise therapy, education, and cognitive behavioral therapy alone, or in combination with total knee arthroplasty, in patients with knee osteoarthritis: a randomized feasibility study

BACKGROUND

One in five patients experience chronic pain 1 year after total knee arthroplasty (TKA), highlighting the need for enhanced treatment strategies to improve outcomes. This feasibility trial aimed to optimize the content and delivery of a complex intervention tailored to osteoarthritis (OA) patients at risk of poor outcome after TKA and assess the feasibility of initiating a full-scale multicenter randomized controlled trial (RCT).

METHODS

Patients scheduled for TKA were included between August 2019 and June 2020 and block-randomized into one of three groups: (a) 12-week exercise therapy and education (ExE) and 10-module internet-delivered cognitive behavioral therapy (iCBT), (b) TKA followed by ExE and iCBT and (c) TKA and standard postoperative care. Outcomes were (i) recruitment and retention rate, (ii) compliance to the intervention and follow-up, (iii) crossover, and (iv) adverse events, reported by descriptive statistics.

RESULTS

Fifteen patients were included in the study. Only 1 out of 146 patients screened for eligibility was included during the first 4 months. During the next 3 months, 117 patients were not included since they lived too far from the hospital. To increase the recruitment rate, we made three amendments to the inclusion criteria; (1) at-risk screening of poor TKA outcome was removed as an eligibility criterion, (2) patients across the country could be included in the study and (3) physiotherapists without specific certification were included, receiving thorough information and support. No patients withdrew from the study or crossed over to surgery during the first year. Nine out of 10 patients completed the ExE program and six out of 10 completed the iCBT program. Fourteen out of 15 patients completed the 1-year follow-up. One minor adverse event was registered.

CONCLUSIONS

Except for recruitment and compliance to iCBT, feasibility was demonstrated. The initial recruitment process was challenging, and necessary changes were made to increase the recruitment rate. The findings informed how a definitive RCT should be undertaken to test the effectiveness of the complex intervention.

TRIAL REGISTRATION

The MultiKnee RCT, including the feasibility study, is pre-registered at ClinicalTrials.gov: NCT03771430 11/12/2018.

Does Computer Navigation or Robotic Assistance Affect the Risk of Periprosthetic Joint Infection in Primary Total Knee Arthroplasty? A Propensity Score-Matched Cohort Analysis

BACKGROUND

The use of technology during total knee arthroplasty (TKA) has been associated with more accurate component position and less blood loss. Yet to date, the risk of developing prosthetic joint infection (PJI) associated with computer navigation (CN) or robotic assistance (RA) has not been thoroughly evaluated. This study used propensity score-matching (PSM) in a large cohort of primary TKA patients to compare the rate of PJI following conventional TKA (TKA) versus CN-TKA and RA-TKA.

METHODS

We retrospectively reviewed 13,015 knees in 11,727 patients who underwent primary TKA at a single institution from 2018 to 2021. The cohort was stratified into TKA, CN-TKA, and RA-TKA groups. 1:1 PSM was applied to 11,834 patients. Propensity score-matching was performed using logistic regression accounting for age, sex, body mass index, Charlson Comorbidity Index (CCI) score, CCI components, and smoking status. Univariate and multivariable analyses were performed to evaluate differences in surgical time and PJI rate.

RESULTS

Significantly longer median operating times were noted in the RA-TKA group (14 minutes) compared to TKA (P < .001). The PJI rates among matched cohorts were similar among RA-TKA (0.3%), CN-TKA (0.3%), and conventional TKA (0.5%). Multivariable logistic regressions demonstrated that the use of robotic assistance (odds ratio (OR) = 0.5, P = .423) or computer navigation (OR = 0.61, P = .128) was not associated with increased risk of PJI when compared to conventional TKA.

CONCLUSIONS

Use of computer navigation and robotic assistance during primary TKA are associated with longer surgical times, but no difference in PJI frequency within 90 days of surgery.

No difference in patient-reported outcomes with cruciate-retaining, anterior-stabilized, and posterior-stabilized total knee arthroplasty designs

Aims

This study compared patient-reported outcomes of three total knee arthroplasty (TKA) designs from one manufacturer: one cruciate-retaining (CR) design, and two cruciate-sacrificing designs, anterior-stabilized (AS) and posterior-stabilized (PS).

Methods

Patients scheduled for primary TKA were included in a single-centre, prospective, three-armed, blinded randomized trial (n = 216; 72 per group). After intraoperative confirmation of posterior cruciate ligament (PCL) integrity, patients were randomly allocated to receive a CR, AS, or PS design from the same TKA system. Insertion of an AS or PS design required PCL resection. The primary outcome was the mean score of all five subscales of the Knee injury and Osteoarthritis Outcome Score (KOOS) at two-year follow-up. Secondary outcomes included all KOOS subscales, Oxford Knee Score, EuroQol five-dimension health questionnaire, EuroQol visual analogue scale, range of motion (ROM), and willingness to undergo the operation again. Patient satisfaction was also assessed.

Results

Patients reported similar levels of pain, function, satisfaction, and general health regardless of the prosthetic design they received. Mean maximal flexion (129° (95% confidence interval (CI) 127° to 131°) was greater in the PS group than in the CR (120° (95% CI 121° to 124°)) and AS groups (122° (95% CI 120° to 124°)).

Conclusion

Despite differences in design and constraint, CR, AS, and PS designs from a single TKA system resulted in no differences in patient-reported outcomes at two-year follow-up. PS patients had statistically better ROM, but the clinical significance of this finding is unclear.

Decreased patient comorbidities and post-operative complications in technology-assisted compared to conventional total knee arthroplasty

PURPOSE

The use of computer-assisted and robotic surgery was developed to improve component position and outcomes of total knee arthroplasty (TKA). The goal of this study is to identify differences in patient demographics, comorbidities, and complications between technology-assisted and conventional TKA.

METHODS

A Nationwide Inpatient Sample database was used to identify patients who underwent technology-assisted and conventional TKA from 2016 to 2018. Analysed variables include demographics, length of stay (LOS), payer-status, geographic region, comorbidities, complications, and mortality. Univariate and multivariate analyses were performed to identify differences between both groups.

RESULTS

The analysis includes 2,208,434 TKA patients, of which 2,054,879 (93.05%) were conventional and 153,555 (6.95%) were technology assisted. Patients undergoing technology-assisted TKA were more likely to be older than 65 years, had higher median income quartile, and had surgery in urban teaching hospitals. Patients were less likely to undergo technology-assisted TKA if they were female gender, had Medicare payer status, were black race, were obese, were living in rural location, or had higher Charlson comorbidity score and baseline comorbidities. Technology-assisted TKA patients had shorter LOS, and fewer pulmonary and infection complications.

CONCLUSION

Patients undergoing technology-assisted TKA are being carefully selected with less baseline comorbidities, improved health, and living in urban areas. Subsequently, those carefully selected patients are discharged home, have a shorted hospital LOS, and have fewer complications compared to conventional TKA. Rural patients, black race and female gender are less likely to undergo technology-assisted TKA, further emphasizing the healthcare disparity for that segment of the population.

LEVEL OF EVIDENCE

Therapeutic level III.

Effect of Tibial Slope on Coronal Alignment in Total Knee Arthroplasty

Malalignment of total knee arthroplasty (TKA) components affects function and survivorship. Common practice is to set coronal alignment prior to adjusting slope. With improper jig placement, adjustment of the slope may alter coronal alignment. The purpose of this study was to quantify the change in coronal alignment with increasing posterior tibial slope while comparing two methods of jig fixation. A prospective consecutive series of 100 patients underwent TKA using computer navigation. Fifty patients had the extramedullary cutting jig secured proximally with one pin and 50 patients had the jig secured proximally with two pins. Coronal alignment (CA) was recorded with each increasing degree of posterior slope (PS) from 0 to 7 degrees. Mean CA and change in CA were compared between cohorts. Utilizing one pin, osteotomies drifted into varus with an average change in CA of 0.34 degrees per degree PS. At 4 degrees PS, patients started to have >3 degrees of varus with 12.0% having >3 degrees of varus at 7 degrees PS. Utilizing two pins, osteotomies drifted into valgus with an average change of 0.04 degrees in CA per degree PS. No patients in the two-pin cohort fell outside 3 degrees varus/valgus CA. CA was significantly different at all degrees of PS between the cohorts. Changes in PS influenced CA making verification of tibial cut intraoperative critical. Use of >1 pin and computer navigation were beneficial to prevent coronal plane malalignment. This relationship may explain why computer navigation has been shown to improve alignment as well as survivorship and outcomes in some patients, especially those <65 years.

Accelerometer-based portable navigation, a faster guide compared to computer-assisted navigation in bilateral total knee arthroplasty-a randomized controlled study

PURPOSE

There are limited studies in the literature comparing the alignment accuracy of  the large console, imageless, computer-assisted navigation (CAN) and portable, hand-held, accelerometer-based navigation (ABN) in total knee arthroplasty (TKA).  This study was aimed to compare the operative time, blood loss, radiological, clinical and functional outcomes between CAN- and ABN-guided bilateral TKA.

METHODS

From Jan 2016 to Dec 2017, 50 patients who underwent bilateral TKA were randomized to undergo either CAN-guided or ABN-guided TKA. Tourniquet time and blood loss were recorded, and intra-op complications were noted. Post-op radiological outcomes at 2 weeks were compared between the groups. The clinical and functional outcomes using the American Knee Society Scores (KSS) and Oxford Knee Score (OKS) were recorded pre-operatively and post-operatively at 3, 6, 12 months and at the end of the study with a minimum follow-up of 48 months.

RESULTS

Both groups were well-matched in terms of patient demographic parameters. The mean surgical time per knee was significantly lower in the ABN group (54.5 ± 5.6 min) compared to the CAN group (61.7 ± 13.7 min; p < 0.01). Mean blood loss per knee in the ABN group was 592.1 ± 245.3 mL compared to 682.8 ± 322.0 in the CAN group (p = 0.11). In the ABN group, the mean post-op mechanical axis was 1.2 ± 3.2° (vs 1.5 ± 2.2° in the CAN group, p 0.6), the frontal femoral angle was 88.8 ± 2.3° (vs 88.8 ± 1.8° in the CAN group, p 1.0) and frontal tibial angle was 90.1 ± 1.6° (vs 89.7 ± 1.1° in the CAN group, p 0.14). At 48 month follow-up, the mean functional KSS in the ABN group was 89.0 ± 5.7 (vs 88.1 ± 4.5 in the CAN group, p 0.37) and the mean OKS was 40.5 ± 2.8 (vs 39.6 ± 3.2 in the CAN group, p 0.12).

CONCLUSION

Portable, hand-held ABN offers alignment accuracy and functional outcomes in TKA similar to that with CAN, with a reduced duration of surgery. There was no advantage of either of the techniques in terms of clinical or functional outcomes at 48 month follow-up. LEVEL OF EVIDENCE 1.

Does fluoroscopy improve baseplate position compared to conventional technique in reverse shoulder arthroplasty? A preliminary study

Background

Accurate placement of glenoid component in reverse shoulder arthroplasty remains a challenge for surgeons of all levels of expertise; however, no studies have evaluated the utility of fluoroscopy as a surgical assistance method.

Methods

Prospective comparative study of 33 patients undergoing primary reverse shoulder arthroplasty during a 12-month period. Fifteen patients had a baseplate placed using the conventional "free hand" technique (control group), and 18 patients using intraoperative fluoroscopy assistance group, in a case-control design. Postoperative glenoid position was evaluated on postoperative Computed Tomography (CT) scan.

Results

The mean deviation of version and inclination for fluoroscopy assistance vs. control group was 1.75° (0.675-3.125) vs. 4.2° (1.975-10.45) (p = .015), and 3.85° (0-7.225) vs. 10.35° (4.35-18.75) (p = .009). The distance from the central peg midpoint to the inferior glenoid rim (fluoroscopy assistance 14.61 mm/control 4.75 mm, p = .581) and the surgical time (fluoroscopy assistance 1.93 ± 0.57/control 2.18 ± 0.44 h, p = .400) showed no differences, with an average radiation dose of 0.45 mGy and fluoroscopy time of 14 s.

Conclusions

Accurate axial and coronal scapular plane positioning of glenoid component is improved with intraoperative fluoroscopy at the cost of a greater radiation dose and without differences in surgical time. Comparative studies are needed to determine whether their use in relation to more expensive surgical assistance systems result in similar effectiveness.L evel of evidence : Level III, therapeutic study.

Comparison of navigation systems for total knee arthroplasty: A systematic review and meta-analysis

Background

Component alignment is a crucial factor affecting the clinical outcome of total knee arthroplasty (TKA). Accelerometer-based navigation (ABN) systems were developed to improve the accuracy of alignment during surgery. This study aimed to compare differences in component alignment, clinical outcomes, and surgical duration when using conventional instrumentation (CONI), ABN, and computer navigation (CN) systems.

Methods

A comprehensive literature search was carried out using the Web of Science, Embase, PubMed, and Cochrane databases. Articles that met the eligibility criteria were included in the study. Meta-analyses were performed using the Cochrane Collaboration Review Manager based on Cochrane Review Method. The variables used for the analyses were postoperative clinical outcome (PCO), surgical duration, and component alignment, including the hip-knee-ankle (HKA) angle, coronal femoral angle (CFA), coronal tibial angle (CTA), sagittal femoral angle (SFA), sagittal tibial angle (STA), and the outliers for the mentioned angles. The mean difference (MD) was calculated to determine the difference between the surgical techniques for continuous variables and the odds ratio (OR) was used for the dichotomous outcomes.

Results

The meta-analysis of the CONI and ABN system included 18 studies involving 2,070 TKA procedures, while the comparison of the ABN and CN systems included 5 studies involving 478 TKA procedures. The results showed that the ABN system provided more accurate component alignment for HKA, CFA, CTA, and SFA and produced fewer outliers for HKA, CFA, CTA, and STA. However, while the ABN system also required a significantly longer surgical time than the CONI approach, there was no statistical difference in PCO for the two systems. For the ABN and CN systems, there was no statistical difference in all variables except for the ABN system having a significantly shorter surgical duration.

Conclusion

There was no significant difference in the accuracy of component alignment between the ABN and CN systems, but the ABN approach had a shorter surgical duration and at lower cost. The ABN system also significantly improved the accuracy of component alignment when compared to the CONI approach, although the surgery was longer. However, there was no significant difference in PCO between the CONI, ABN, and CN systems.

Pain Course after Total Knee Arthroplasty within a Standardized Pain Management Concept: A Prospective Observational Study

BACKGROUND

Joint replacement surgeries have been known to be some of the most painful surgical procedures. Therefore, the options for postoperative pain management are of great importance for patients undergoing total knee arthroplasty (TKA). Despite successful surgery, up to 30% of the patients are not satisfied after the operation. The aim of this study is to assess pain development within the first 4 weeks after TKA in order to gain a better understanding and detect possible influencing factors.

METHODS

A total of 103 patients were included in this prospective cohort study. Postoperative pain was indicated using a numeric rating scale (NRS). Furthermore, demographic data and perioperative parameters were correlated with the reported postoperative pain.

RESULTS

The evaluation of postoperative pain scores showed a constant decrease in the first postoperative week (mean NRS score of 5.8 on day 1 to a mean NRS score of 4.6 on day 8). On day 9, the pain increased again. Thereafter, a continuous decrease in pain intensity from day 10 on was noted (continuous to a mean NRS score of 3.0 on day 29). A significant association was found between postoperative pain intensity and gender, body mass index (BMI), and preoperative leg axis.

CONCLUSIONS

The increasing pain score after the first postoperative week is most likely due to more intensive mobilization and physiotherapy in the rehabilitation department. Patients that were female, had a low BMI, and a preoperative valgus leg axis showed a significantly higher postoperative pain scores. Pain management should consider these results in the future to improve patient satisfaction in the postoperative course after TKA.

Dynamic gap analysis of valgus knees shows large inter-individual variability of gaps

PURPOSE

The purpose of this study was to investigate the dynamic gap widths of valgus knees in extension and flexion to evaluate the influence of deformity on gap differences and to find out whether different ligamentous subtypes in valgus knees exist.

METHODS

Dynamic gap widths of 1000 consecutive total knee arthroplasty (TKA) patients were measured at different flexion angles by applying a computer-assisted surgery (CAS) technique. 198 knees showed a valgus deformity and were assessed regarding its degree of fulfillment of the following criteria of valgus knee: 1. Medial extension gap greater than lateral; 2. Medial flexion gap greater than lateral; 3. Flexion gap greater than extension gap. A single-factor ANOVA subgroup analysis was performed, based on the amount of deformity. The effect of other patient factors (age, gender, weight) on gap differences was investigated.

RESULTS

The medial extension gap (3.7 ± 2.2 mm) was significantly (p < 0.01) larger than the lateral extension gap (1.1 ± 2.9 mm). The amount of deformity correlated highly with gap difference in extension (r² = 0.67) but not in flexion. In 92.4% (183), the flexion gap (6.2 ± 3.1 mm) was significantly (p < 0.01) larger than the extension gap (2.4 ± 2.3 mm). Only 29.3% (58) of patients met all three criteria, this was mainly due to the fact that in flexion the medial gap was larger than the lateral in only 35.4% (70). Patient factors showed no significant influences (NS) on the gap widths.

CONCLUSION

Valgus knees show large variability in terms of gap widths. The extent of deformity correlates highly with gap difference in extension, but not in other flexion angles. Vast majority of valgus knees were valgus in extension only. Because of this variability, it should be aimed for an individualized balancing technique based on intraoperative gap sizes.

LEVEL OF EVIDENCE

Level III.

Accelerometer-based navigation vs. conventional techniques for total knee arthroplasty (TKA): a systematic review and meta-analysis of randomized controlled trials

Background

The aim of the study was to determine whether accelerometer-based navigation (ABN) can improve radiological and functional outcomes during total knee arthroplasty (TKA) compared with conventional techniques (CONV).

Method

We comprehensively searched the PubMed, Embase, Web of Science, Cochrane Library, and Clinical Trials databases. Only randomized controlled trials were selected for meta-analysis and, ultimately, 10 studies were included.

Results

The 10 studies involved 1,125 knees, of which 573 were in the ABN group and 552 in the CONV group. The results demonstrated that ABN significantly reduced the number of outliers for mechanical alignment (MA) (RR: 0.38, 95% CI: 0.27 to 0.54, P < 0.00001, I² = 45%), achieving more accurate MA (RR: –0.78, 95% CI: –0.93 to –0.62, P < 0.00001, I² = 76%). The results revealed that there was no significant difference in duration of surgery between the ABN and CONV groups (MD: –0.2, 95% CI: –1.45 to 1.05, P = 0.75, I² = 48%). There was less blood loss through the use of ABN (SMD: –0.49, 95% CI: –0.93 to –0.06, P = 0.03, I² = 75%). However, ABN group didn’t show better knee function (SMD: 0.13, 95% CI: –0.07 to 0.33, P = 0.20, I² = 0%), though the incidence of overall complications was significantly lower (RR: 0.69, 95% CI: 0.50 to 0.95, P = 0.02, I² = 0%).

Conclusions

The present meta-analysis demonstrated that ABN was superior to CONV in restoring MA of the lower limb. In addition, ABN reduced the loss of blood and the duration of surgery was not prolonged. However, patient-reported outcome measurements (PROMs) were not improved.

Use of intraoperative technology in total knee arthroplasty is not associated with reductions in postoperative pain

PURPOSE

Our systematic review and meta-analysis sought to assess how technology-assistance impacts (1) post-operative pain and (2) opioid use in patients undergoing primary total knee arthroplasty (TKA).

METHODS

Four online databases were queried for studies published up to October 2021 that reported on pain and opioid usage between technology-assisted and manual TKA (mTKA) patients. Mantel-Haenszel (M-H) models were utilized to calculate pooled mean difference (MDs) and 95% confidence interval (CIs). Subgroup analyses were conducted to isolate robotic-arm assisted (RAA) and computed-assisted navigation (CAN) cohorts. Risk of bias was assessed for all included non-randomized studies with the Methodological Index for Non-Randomized Studies (MINORS) tool. For the randomized control trials included in our study, the Detsky scale was applied.

RESULTS

Our analysis included 31 studies, reporting on a total of 761,300 TKAs (mTKA: n = 753,554; Computer-Assisted Navigation (CAN): n = 1,309; Robotic-Arm Assisted (RAA): n = 6437). No differences were demonstrated when evaluating WOMAC (MD: 0.00, 95% CI - 0.69 to 0.69; p = 1.00), KSS (MD: 0.01, 95% CI - 1.46 to 1.49; p = 0.99), KOOS (MD - 2.91, 95% CI - 6.17 to 0.34; p = 0.08), and VAS (MD - 0.54, 95% CI - 1.01 to - 0.007; p = 0.02) pain scores between cohorts. There was mixed evidence regarding how opioid consumption differed between TKA techniques.

CONCLUSION

The present analysis demonstrated no difference in terms of pain across a variety of utilized patient-reported pain measurements. However, there were mixed results regarding how opioid consumption varied between manual and technology-assisted cohorts, particularly in the immediate post-operative period.

LEVEL OF EVIDENCE

III.

Navigated and Robot-Assisted Technology in Total Knee Arthroplasty: Do Outcome Differences Achieve Minimal Clinically Important Difference?

BACKGROUND

In total knee arthroplasty (TKA), computer-assisted navigation (N-TKA) and robotic-assisted methods (RA-TKA) are intended to increase precision of mechanical and component alignment. However, the clinical significance of published patient-reported outcome measure (PROM) differences in comparison to conventional TKA (C-TKA) is unknown.

METHODS

A systematic review was performed to identify all studies reporting perioperative PROMs for either primary N-TKA or RA-TKA with a C-TKA comparison cohort with a minimum 1-year follow-up. Relative improvements in PROMs for the two cohorts were compared to published minimal clinically important difference (MCID) values.

RESULTS

After systematic review, 21 studies (N = 3,214) reporting on N-TKA and eight studies (N = 1,529) reporting on RA-TKA met inclusion criteria. Eighteen of 20 studies (90%) reported improved radiographic outcomes with N-TKA relative to C-TKA; five of five studies reported improved radiographic outcomes with RA-TKA relative to C-TKA. Five of 21 studies (24%) reported statistically significant greater improvements in clinical PROMs for N-TKA relative to C-TKA, whereas only two (10%) achieved clinical significance relative to MCID on a secondary analysis. One of 8 studies (13%) reported statistically significant greater improvements in PROMs for RA-TKA relative to C-TKA, whereas none achieved clinical significance relative to MCID on a secondary analysis. No studies reported a significant difference in revision rates.

CONCLUSION

While most studies comparing RA-TKA and N-TKA with C-TKA demonstrate improved radiographic alignment outcomes, a minority of studies reported PROM differences that achieve clinical significance. Future studies should report data and be interpreted in the context of clinical significance to establish patient and surgeon expectations for emerging technologies.

A single type of varus knee does not exist: morphotyping and gap analysis in varus OA

PURPOSE

To achieve a higher level of satisfaction in patients having undergone Total Knee Arthroplasty (TKA), a more personalized approach has been discussed recently. It can be assumed that a more profound knowledge of bony morphology and ligamentous situation would be beneficial. While CT/MRI can give 3D information on bone morphology, the understanding of the ligamentous situation in different flexion angles is still incomplete. In this study, the dynamic gap widths of a large number of varus knees were assessed in various flexion angles, to find out whether all varus knees behave similar or have more individual soft tissue patterns. Additionally, it was investigated whether the amount of varus deformity or other patient factors have an effect on joint gap widths.

METHODS

A series of 1000 consecutive TKA patients, including their CAS data and patient records were analyzed. Joint gap widths in multiple flexion angles (0°, 30°, 60°, 90°) were measured in mm and differences between the joint gaps were compared. A "standard" varus knee was defined as follows: (1) Lateral extension gap greater than medial, (2) lateral flexion gap greater than medial, and (3) flexion gap greater than extension gap. The percentage of fulfillment was tested for each and all criteria. To measure the influence of varus deformity on gap width difference, three subgroups were formed based on the deformity. Data were analyzed at 0°, 30°, 60° and 90° flexion. The effect of patient factors (gender, BMI, age) on gap sizes was tested by performing subgroup analyses.

RESULTS

Only 444 of 680 (65%) patients met all three varus knee criteria. The lateral extension gap (4.1 mm) was significantly larger than the medial extension gap (0.6 mm) in 657 (97%) patients and the gap difference highly correlated with the amount of varus deformity (r² = 0.62). In all flexion positions, however, no correlation between gap differences and varus deformity existed. Women had significantly larger extension and flexion gaps. Age and BMI showed no significant effect on gap widths.

CONCLUSION

Varus knees show a large inter-individual variability regarding gap widths and gap differences. The amount of varus deformity correlates highly with the medio-lateral gap difference in extension, but not in any flexion angle. As varus knees are not all alike, a uniform surgical technique will not treat all varus knees adequately and the individual gap sizes need to be analyzed and addressed accordingly with an individualized balancing technique. Which final balancing goal should be achieved needs to be analyzed in future studies.

LEVEL OF EVIDENCE

Level III.

Imageless Computer Navigation Reduces 5-Year All-Cause Revision Rates After Primary Total Knee Arthroplasty

BACKGROUND

The use of surgical navigation has been shown to reduce revision rates after total knee arthroplasty (TKA) in patients <65 years of age. It is unknown if this benefit extends to older patients. We hypothesized that the use of surgical navigation would reduce rates of all-cause revision in patients of all ages.

METHODS

In this cohort study, we queried the Truven MarketScan all-payer database to identify patients who underwent TKA from 2007 to 2015. Current Procedural Terminology codes were used to create 2 groups based on whether intraoperative navigation was used. Demographics, comorbidities, complications, and revision rates were determined. International Classification of Diseases codes were used to determine reasons for revision.

RESULTS

The conventional TKA cohort included 312,173 patients. The navigation cohort included 20,881 patients. There were not any clinically significant differences in demographics between the cohorts. All-cause revision rates were lower in the navigation cohort at 1 year (0.4% vs 0.5%, P = .04), 2 years (0.7% vs 0.9%, P = .003), and 5 years (0.9% vs 1.3%, P < .001) of follow-up. Revisions for mechanical loosening were more common in the conventional cohort (30.8% vs 21.9%, P = .009). Rates of revision for other causes, including infection, did not differ between groups, with the numbers available.

CONCLUSION

The use of surgical navigation yielded a 30.7% reduction in the all-cause revision rate at 5-year follow-up compared to conventional TKA. This benefit increased as follow-up duration increased. Increased usage of this inexpensive technology, from the current 6.3% in this US cohort, may reduce healthcare costs.

LEVEL OF EVIDENCE

III.

The effectiveness of exercise therapy and education plus cognitive behavioral therapy, alone or in combination with total knee arthroplasty in patients with knee osteoarthritis - study protocol for the MultiKnee trial

Background

One in five patients report chronic pain following total knee arthroplasty (TKA) and are considered non-improvers. Psychological interventions such as cognitive behavioral therapy (CBT), combined with exercise therapy and education may contribute to reduced pain an improved function both for patients with OA or after TKA surgery, but the evidence for the effectiveness of such interventions is scarce. This randomized controlled trial with three arms will compare the clinical effectiveness of patient education and exercise therapy combined with internet-delivered CBT (iCBT), evaluated either as a non-surgical treatment choice or in combination with TKA, in comparison to usual treatment with TKA in patients with knee OA who are considered candidates for TKA surgery.

Methods

The study, conducted in three orthopaedic centers in Norway will include 282 patients between ages 18 and 80, eligible for TKA. Patients will be randomized to receive the exercise therapy + iCBT, either alone or in combination with TKA, or to a control group who will undergo conventional TKA and usual care physiotherapy following surgery. The exercise therapy will include 24 one hour sessions over 12 weeks led by a physiotherapist. The iCBT program will be delivered in ten modules. The physiotherapists will receive theoretical and practical training to advise and mentor the patients during the iCBT program. The primary outcome will be change from baseline to 12 months on the pain sub-scale from the Knee Injury and Osteoarthritis Outcome Score (KOOS). Secondary outcomes include the remaining 4 sub-scales from the KOOS (symptoms, function in daily living, function in sports and recreation, and knee-related quality of life), EQ-5D-5L, the Pain Catastrophizing Scale, the 30-s sit-to-stand test, 40-m walking test and ActiGraph activity measures. A cost-utility analysis will be performed using QALYs derived from the EQ-5D-5L and registry data.

Discussion

This is the first randomized controlled trial to investigate the effectiveness of exercise therapy and iCBT with or without TKA, to optimize outcomes for TKA patients. Findings from this trial will contribute to evidence-based personalized treatment recommendations for a large proportion of OA patients who currently lack an effective treatment option.

Trial registration

Clinicaltrials.gov: NCT03771430. Registered: Dec 11, 2018.

Assistive technologies in knee arthroplasty: fashion or evolution? Rate of publications and national registries prove the Scott Parabola wrong

PURPOSE

Most opponents of assistive technologies in orthopedic surgery consider them as a marketing ruse or fashion. Our hypothesis was that many innovations in modern knee arthroplasty are not following the Scott Parabola. This parabola represents the visual curve of a procedure or therapy showing great promise at the beginning, becoming the standard treatment after reports of encouraging results, only to fall into disuse due to adverse outcome reports. This study aimed to assess the interest in these assistive technologies by (1) their number of publications/year and (2) their actual surgical use reported in the National Joint Registries.

METHODS

The search was performed through PubMed, EMBASE, and MEDLINE databases from 1997 to 2021 inclusive to identify all available literature that described the use and results of assistive technologies or new surgical techniques in knee arthroplasty. In the Australian and Norwegian registries, the number of cases performed with these techniques in knee arthroplasty has been quantified year by year.

RESULTS

Following the initial online search, a total of 4085 articles was found. After the assessment mentioned above, 2106 articles were included in the study. The orthopedic techniques assessed in this study are not following the "Scott's parabola" in the literature. Computer-assisted knee arthroplasty and patient-specific instrumentation have increased quickly to have reached a plateau, with a stable number of publications over the last 6 years. The number of publications concerning robotic surgery, accelerometers and sensors continue to rise. In the Australian registry, the proportion of primary TKA performed by computer-assisted systems increased from 2.4% in 2003 to 32% in 2019. In the Norwegian registry, the proportion of computer-assisted TKA remained between 8 and 12% of primary TKA since 2007.

CONCLUSION

Most of the innovations in modern knee arthroplasty are not following the Scott Parabola. After a fast rise, these techniques do not disappear but continue to evolve. Their evolution is synergistic, and techniques appeared to be linked to each other's. Despite persisting concerns about the cost-efficiency of assisting technologies in knee arthroplasties, the interest and use do not decrease and seems to be directly linked to an exponential increase in interest for a better understanding of alignment targets and improved functional recovery.

Patient expectations and satisfaction in robotic-assisted total knee arthroplasty: a prospective two-year outcome study

INTRODUCTION

The impact of fulfillment of patient expectations throughout recovery on satisfaction in total knee arthroplasty (TKA) is not well understood. Utilizing a standardized TKA method with a robotically assisted (RA) platform, we investigated the impact of expectation fulfillment at 3-month (M) and 6-M on 1-year (Y) and 2-Y satisfaction. We hypothesize that early fulfillment of patient expectations is associated with improved midterm patient satisfaction. We also compare improvements in outcomes with RA-TKA to those of a recent large national TKA cohort study to determine whether RA-TKA meets or exceeds the current standard of care.

MATERIALS AND METHODS

One hundred six patients were prospectively enrolled and underwent robotic-assisted TKA by a single surgeon using the OMNIBotics system. Patients completed KOOS and New Knee Society Score (KSS) preoperatively and at 3M, 6M, 1Y, and 2Y postoperatively. Expectation fulfillment was subdivided into patients who were below or above the average expectation score pre-operatively, or fulfillment of expectation score at 3M and 6M post TKA. The satisfaction of each group was then compared at 1Y and 2Y post TKA. Study cohort outcomes were compared to contemporary literature from the Function and Outcomes Research for Comparative Effectiveness in Total Joint Replacement (FORCE-TJR) database.

RESULTS

Patients with greater than average KSS expectation fulfillment at 3M reported significantly higher KSS satisfaction scores at 1Y (34.9 ± 5.3 vs 30.6 ± 6.7, p = 0.0012), and patients with greater than average 6M expectation fulfillment reported improved satisfaction at 1Y (33.9 ± 5.9 vs 31.1 ± 6.7, p = 0.0330) and 2Y (35.2 ± 4.8 vs 32.4 ± 6.8, p = 0.0323). When compared to the FORCE-TJR database, no significant differences in post-operative KOOS outcomes were observed except for Sports and Recreation, for which the RAS group demonstrated higher scores (65.5 ± 30.0 vs 53.0 ± 27.1 p < 0.0001); however, the study cohort reported significantly greater improvements in KOOS Pain, Symptoms, Sports and Recreation, and Quality of Life at multiple time points up to 2 years post TKA.

CONCLUSION

High early-expectation fulfillment was associated with improved satisfaction at 1Y and 2Y, indicating the importance of managing patient-specific post-operative care to ensure patients reach their pre-operative goals. Greater improvements in all KOOS sub-scores and in absolute Sports and Recreation at 1Y and 2Y were observed in this robotic-assisted cohort compared to a large contemporary database, indicating that RAS meets or exceeds current standard of care benchmarks for patient-reported outcomes.

Comparison of Existing and New Total Knee Arthroplasty Implant Systems From the Same Manufacturer: A Prospective, Multicenter Study

This study evaluated total knee arthroplasty (TKA) outcomes for an Existing-TKA versus New-TKA from the same manufacturer.

Fragility Index as a Measure of Randomized Clinical Trial Quality in Adult Reconstruction: A Systematic Review

Background

The Fragility Index (FI) and Reverse Fragility Index are powerful tools to supplement the P value in evaluation of randomized clinical trial (RCT) outcomes. These metrics are defined as the number of patients needed to change the significance level of an outcome. The purpose of this study was to calculate these metrics for published RCTs in total joint arthroplasty (TJA).

Methods

We performed a systematic review of RCTs in TJA over the last decade. For each study, we calculated the FI (for statistically significant outcomes) or Reverse Fragility Index (for nonstatistically significant outcomes) for all dichotomous, categorical outcomes. We also used the Pearson correlation coefficient to evaluate publication-level variables.

Results

We included 104 studies with 473 outcomes; 92 were significant, and 381 were nonstatistically significant. The median FI was 6 overall and 4 and 7 for significant and nonsignificant outcomes, respectively. There was a positive correlation between FI and sample size (R = 0.14, P = .002) and between FI and P values (R = 0.197, P = .000012).

Conclusions

This study is the largest evaluation of FI in orthopedics literature to date. We found a median FI that was comparable to or higher than FIs calculated in other orthopedic subspecialties. Although the mean and median FIs were greater than the 2 recommended by the American Academy of Orthopaedic Surgeons Clinical Practice Guidelines to demonstrate strong evidence, a large percentage of studies have an FI < 2. This suggests that the TJA literature is on par or slightly better than other subspecialties, but improvements must be made.

Level of Evidence

Level I; Systematic Review.

The in vivo impact of computer navigation on screw number and length in reverse total shoulder arthroplasty

BACKGROUND

Little information exists regarding the benefit of computer navigation in shoulder arthroplasty in the clinical setting. This study aimed to quantify how computer navigation affects the number and length of screws used during in vivo reverse total shoulder arthroplasty (RSA) placement.

METHODS

We performed a retrospective review of a research database to identify patients who underwent primary RSA before and after the use of computer navigation between January 1, 2015, and December 31, 2019. One hundred consecutive RSAs were selected from the computer navigation implantation date; then, 100 consecutive sex-matched RSAs were chosen prior to navigation implantation in reverse chronologic order. Baseplate augmentations were chosen based on surgeon discretion, with the goal of restoring version to within 10° of neutral and inclination to neutral or slightly inferior with removal of the smallest amount of subchondral bone possible. Screws were placed with the goal of ≥3 screws with good purchase and were added as needed, with up to 5 screws used. We compared demographic factors, comorbidities, preoperative diagnosis, number of screws, screw length, number of wasted screws, and number of cases with bone graft used behind the baseplate between the 2 groups. We used the χ² test for bivariate analysis and the Student t test for continuous variables.

RESULTS

A total of 200 RSAs were included, with 100 primary RSAs (mean age, 69.3 years) performed prior to computer navigation compared with 100 primary RSAs (mean age, 69.7 years) performed using computer navigation. The total number of screws used in RSAs without computer navigation was 414; the total used in the computer navigation cases was 344. RSAs placed with computer navigation used significantly fewer screws per case (3.4 screws vs. 4.1 screws, P < .001) and had a significantly greater average screw length (35.0 mm vs. 32.6 mm, P < .001). Three screws were implanted in 61% of computer navigation cases vs. 1% of cases without computer navigation (P < .001). Screws ≥ 30 mm in length were more commonly used in patients undergoing RSA using computer navigation (84.6% vs. 73.7%, P < .001).

CONCLUSION

This study shows that computer navigation in RSA leads to longer and fewer glenoid baseplate screws being implanted. Computer navigation appears to assist with better screw placement, which may have similar clinical benefits of better glenoid fixation. Additionally, using fewer screws can save glenoid bone stock, avoid added glenoid stress risers, and decrease operative time.

Benefits of CT Scanning for the Management of Knee Arthritis and Arthroplasty

This review investigated the potential value of computed tomography (CT) scans for the evaluation and management of knee arthritis and arthroplasty. Specifically, we evaluated the following: (1) assessment of arthritis within knee compartments, (2) patellofemoral joint assessment, (3) implant sizing prediction, (4) component alignment, (5) soft-tissue protection, and (6) potential concerns with radiation exposure. To compare if CT or X-ray imaging is more accurate and clinically relevant, a search was performed using Boolean search operators and terms: "CT," "radiograph," "joint alignment," "knee," and "arthroplasty," which yielded 661 results. Studies were evaluated based on (1) assessment of arthritis within knee compartments, (2) patellofemoral joint assessment, (3) implant sizing prediction, (4) component alignment, (5) soft-tissue protection, and (6) potential concerns with radiation exposure. Correlative and comparative analyses of imaging modalities to pre-, intra-, and postoperative clinical and patient-related factors were performed for the 63 included studies. CT scans were found to better detect medial and lateral arthritic changes, bony deformities, subchondral cysts, and cartilage losses. CT scans were shown to 99% accurately predict prosthetic sizes preoperatively. CT scans can also help better visualize surrounding anatomy, such as the posterior cruciate ligament, and have therefore been linked to better soft tissue protection during total knee arthroplasty. Although radiation is a potential concern, newer imaging protocols have comparable exposure to plain radiographs. Compared with plain radiographs, CT scans were found to be more accurate and provide more clinically relevant data. Therefore, the authors recommend the use of CT for the evaluation of certain patients with arthritis and for preoperative planning for knee arthroplasty.

Clinical outcomes associated with robotic and computer-navigated total knee arthroplasty: a machine learning-augmented systematic review

BACKGROUND

Robotic (RTKA) and computer-navigated total knee arthroplasty (CNTKA) are increasingly replacing manual techniques in orthopaedic surgery. This systematic review compared clinical outcomes associated with RTKA and CNTKA and investigated the utility of natural language processing (NLP) for the literature synthesis.

METHODS

A comprehensive search strategy was implemented. Results of included studies were combined and analysed. A transfer learning approach was applied to train deep NLP classifiers (BERT, RoBERTa and XLNet), with cross-validation, to partially automate the systematic review process.

RESULTS

52 studies were included, comprising 5,067 RTKA and 2,108 CNTKA. Complication rates were 0-22% and 0-16% and surgical time was 70-116 and 77-102 min for RTKA and CNTKA, respectively. Technical failures were more commonly associated with RTKA (8%) than CNTKA (2-4%). Patient satisfaction was equivalent (94%). RTKA was associated with a higher likelihood of achieving target alignment, less femoral notching, shorter operative time and shorter length of stay. NLP models demonstrated moderate performance (AUC = 0.65-0.68).

CONCLUSIONS

RTKA and CNTKA appear to be associated with similarly positive clinical outcomes. Further work is required to determine whether the two techniques differ significantly with regard to specific outcome measures. NLP shows promise for facilitating the systematic review process.

Computer-Navigated versus Conventional Total Knee Arthroplasty: A Meta-Analysis of Functional Outcomes from Level I and II Randomized Controlled Trials

The main purpose of this article is to provide an up-to-date systematic review and meta-analysis comparing functional outcomes of total knee arthroplasty using either computer navigation (NAV-TKA) or conventional methods (CON-TKA) from the latest assemblage of evidence. This study was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Meta-Analysis of Observational Studies in Epidemiology guidelines. All Level I and II randomized controlled trials (RCTs) in PubMed, EMBASE, and Cochrane that compared functional outcomes after NAV- and CON-TKA were included in the review. Selected end points for random effects, pairwise meta-analysis included Knee Society Knee Score (KSKS), KS Function Score (KSFS), KS Total Score (KSTS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and range of motion at three arbitrary follow-up times. A total of 24 prospective RCTs comprising 3,778 knees were included from the initial search. At long-term follow-up (>5 years), NAV-TKA exhibited significantly better raw KSKS (p = 0.001) (low-quality evidence), contrary to CON-TKA, which reflected significantly better raw KSTS (p = 0.004) (high-quality evidence). While change scores (KSKS, WOMAC) from preoperative values favor CON-TKA at short-term (<6 months) and medium-term follow-up (6-60 months), long-term follow-up change scores in KSKS suggest the superiority of NAV-TKA over CON-TKA (p = 0.02) (very low-quality evidence). Overall, sizeable dispersion of nonstatistically significant functional outcomes in the medium term was observed to eventually converge in the long term, with less differences in functional outcome scores between the two treatment methods in short- and long-term follow-up. While raw functional outcome scores reflect no differences between NAV and CON-TKA, long-term follow-up change scores in KSKS suggest superiority of NAV-TKA over its conventional counterpart. Prospective studies with larger power are required to support the pattern of diminishing differences in functional outcome scores from medium- to long-term follow-up between the two modalities.

The cost-effectiveness of computer navigation in primary total knee replacement: a scoping review

Despite additional costs associated with the use of computer navigation technology in total knee replacement (TKR), its impact on quality-adjusted life years following surgery has not been demonstrated. Cost-effectiveness evaluations require a balanced assessment of both quality and cost metrics.This review sought to evaluate the cost-effectiveness of computer navigation, identify barriers to translation, and suggest directions for further investigation. A systematic search of the Cost-Effectiveness Analysis Registry, PubMed, and Embase was undertaken.Cost-effectiveness analyses of computer navigation in primary total knee replacement were identified. Only primary studies of cost-effectiveness analyses published in the English language from the year 2000 onwards were included. Studies that reported secondary data were excluded from the analysis. Four publications met the inclusion criteria.Estimated gains in quality-adjusted life years attributed to reductions in revision surgery were 0.0148 to 0.0164 over 10 years, and 0.0192 (95% CI -0.002 to 0.0473) over 15 years. Cost estimates ranged from 952 kr (US $90, 2020) per case at 250 TKRs/year, to $1,920 US per case at 25 TKRs/year.The estimated probability of meeting local cost-effectiveness thresholds was 54% in the United States and 92% in the United Kingdom. These data were not available for Norway.The cost-effectiveness of computer navigation in current practice settings remains uncertain, with the use of this technology associated with marginal increased quality-adjusted life years (QALYs) at additional cost. Existing analyses demonstrated a number of limitations which restrict the potential for translation to practice and policy settings. Further research evaluating the impact of computer navigation on QALYs following primary TKR is required to inform contemporary cost-effectiveness evaluations. Cite this article: EFORT Open Rev 2021;6:173-180. DOI: 10.1302/2058-5241.6.200073.

No influence of obesity on mid-term clinical, functional, and radiological results after computer-navigated total knee arthroplasty using a gap balancing technique

OBJECTIVE

In obese patients, thick subcutaneous tissue can introduce errors during registration and leg weight can influence gap balancing in navigated TKA. Present study is done to determine if computer navigated TKA using a gap balancing technique can achieve consistent accuracy for limb and component alignment, and similar clinical and functional results in obese patients like in non-obese patients.

METHODS

We prospectively compared the radiological, clinical, and functional results of 78 knees in 57 non-obese patients and 79 knees in 58 obese patients who underwent computer-assisted TKA. Non-obese individuals were defined as those having BMI of <30 kg/m² and obese individuals as BMI ≥30 kg/m². The degree of knee deformity was calculated by Hip - Knee - Ankle (HKA) angle and clinical and functional assessment was done using the Knee Society Score - clinical knee score and Knee Society Score - function score, respectively. All these were documented before and at 6 months, 2 year, and 5 years after TKA.

RESULTS

The outlier rate of postoperative limb alignment (HKA angle) was 8.9% in the obese group which was not significantly different (p =1.00) from that of the non-obese group (7.7%). Mean clinical knee scores were not significantly different between the non-obese and obese groups preoperatively (58.8 vs 57.4, p = 0.14) and at 6 months (92.7 vs 91, p = 0.06), 2 years (91.4 vs 90, p = 0.07), and 5 years (92.4 vs 91.3, p = 0.1) post-surgery. Similarly, mean functional scores were not significantly different between the non-obese and obese groups preoperatively (50.9 vs 49.9, p = 0.31) and at 6 months (92.7 vs 90.9, p = 0.06), 2 years (91.3 vs 92, p = 0.44), and 5 years (90.6 vs 91.1, p = 0.51) post-surgery.

CONCLUSION

Obesity has no influence on mid-term clinical, functional, and radiological results after computer navigated TKA, done by gap balancing technique.

LEVEL OF EVIDENCE

Therapeutic level II.

Computer assisted total knee arthroplasty: 2.5 years follow-up of 200 cases

INTRODUCTION

Computer assisted surgery in total knee arthroplasty (TKA) should improve accuracy of both femoral and tibial components placement. This study evaluated the functional outcomes of computer navigated total knee arthroplasty through the Knee Society Score (KSS) and Tegner Lysholm Knee Scoring Scale (TLKSS).

MATERIALS AND METHODS

Between September 2007 and February 2013, 180 patients (200 knees; 109 females and 71 males; mean age: 64 years) undergoing computer-assisted TKA were recruited. Plain radiographs and CT scans were performed post-operatively to evaluate alignment. The clinical outcomes were measured using the KSS and TLKSS pre-operatively and after 6, 12 and 36 months.

RESULTS

The mean follow-up duration was 2.5 years. The mean tourniquet time was 72 ± 13.4 min, and patients received an average of 0.6 ± 0.82 units of blood after surgery. The average preoperative KSS functional score of 44.6 ± 13.7 improved to 80.4 ± 16.4 after 2 years. The average preoperative TLKSS improved to 71.4 ± 13.5 after 2 years. The mechanical axis was within ±3° in all patients. No axial malalignments were observed on TC Scan. Three patients (1.6% of cases) required revision.

CONCLUSION

Computer assisted TKA allows reproducible alignment and kinematics, reducing outliers, provides ligament balancing and ensures good short term outcomes in terms of KSS functional score and TLKSS.

A novel augmented reality-based surgical guidance system for total knee arthroplasty

INTRODUCTION

Many of the functional complications that arise after total knee arthroplasty (TKA) are caused by a non-optimal balance of the knee after surgery. Over the past 20 years, technology has been used in the Operating Room (OR) to help improve precision and balance. The results of Computer-Assisted Surgery (CAS) and robotic systems show improved accuracy regarding implant positioning but a relatively small improvement in patient-reported outcomes and implant survival compared to conventional TKA. Recently, Augmented Reality (AR) has been proposed as a technology that could improve accuracy in orthopaedic surgery, providing a more efficient and cost-effective solution.

MATERIALS AND METHODS

This article describes a novel AR-based surgical guidance system that measures intra-operatively the effect of prosthesis alignment and positioning on soft tissue balance. The system is integrated in a pair of smart glasses and two small sensors and displays surgical targets directly in the field of view of the surgeon.

RESULTS

The system has been used in a limited number of cases. While the preliminary experience has been positive, clinical research is ongoing to confirm to confirm the performance of the system and the impact on clinical outcomes.

CONCLUSION

Augmented Reality can be a valuable tool to improve accuracy in TKA. The use of smart glasses and integrated sensors improves the efficiency of the procedure, particularly when coupled with single-use instrumentation. A novel protocol for soft tissue assessment allows for a 3-dimensional evaluation of the ligaments and a better measurement of the effect of tibial rotation.

Total Knee Arthroplasty Is Superior to Open Wedge High Tibial Osteotomy in Terms of Pain Relief for Patients With Osteoarthritis

Background

Globally, total knee arthroplasty (TKA) is widely performed on patients with osteoarthritis. Meanwhile, open wedge high tibial osteotomy (OWHTO) has garnered attention in our country as a joint-preserving procedure. This study aimed to retrospectively compare the postoperative clinical outcomes of TKA and OWHTO for patients with osteoarthritis.

Methods

We selected 94 patients (106 knees) who underwent OWHTO or TKA between 2013 and 2018, had complete clinical data, and were followed up for >2 years. Patients were classified into 2 groups depending on the procedure (TKA: n = 49; OWHTO: n = 45). Patients in the A (= arthroplasty) group were significantly older, with a worse range of motion (ROM) than those in the O (osteotomy) group. There were no significant differences regarding sex and body mass index between groups. Operative time, perioperative blood loss, knee ROM, and Japanese Knee Injury and Osteoarthritis Outcome Score (J-KOOS) were compared between the groups.

Results

Significant differences were found between the A and O groups regarding operative time (120 ± 27.2 vs 80.3 ± 23.3 minutes), perioperative blood loss (505.4 ± 271.8 vs 322.6 ± 196.1 mL), knee ROM (flexion; 123.4 ± 16.3° vs 133.7 ± 12.8°), and J-KOOS for pain (87.4 ± 12.5 vs 78.1 ± 15.2 points) and symptoms (86.6 ± 12.3 vs 79.1 ± 13.3 points). There were no significant differences regarding other J-KOOS subscales.

Conclusions

OWHTO involved shorter operative times and less blood loss. However, the O group reported less pain relief. The A group represents an older, likely less active patient population. Therefore, OWHTO is a possible joint-preserving treatment options in younger active patients who may not be interested in arthroplasty.

Limb and component alignment after total knee arthroplasty comparing 28 consecutive iAssist and 28 conventional TKAs: A prospective study

BACKGROUND

The objective of this study was to assess limb and component alignment after total knee arthroplasty (TKA) on long leg X-rays and to compare the use of iAssist, an accelerometric based computer-assisted device (CAD), with conventional jigs.

METHODS

We prospectively recruited 56 consecutive patients undergoing primary unilateral TKA by a single surgeon into this study. In the first 28 patients iAssist navigation system was utilized and in the following 28 conventional jigs were used. The groups were comparable with regard to age, sex distribution, body mass index and preoperative hip-knee-ankle (HKA) angle. Our aim was to restore neutral coronal alignment and a five degree tibial slope.

RESULTS

The mean postoperative mechanical axis was 179.4° in the CAD group and 180.1° in the conventional group (P = 0.187). There were five TKAs deviating more than three degrees from neutral (18.5%) in the conventional group and none in the CAD group (P = 0.051). The mean femoral mechanical-condyles-angle was significantly closer (P < 0.001) to our target of 90° in the conventional group but contained more outliers (P = 0.67). The sagittal tibial slope was closer (P = 0.047) to our target of 85° in CAD-navigated TKAs with fewer outliers (P < 0.0001). The Oxford Knee Score showed comparable (P = 0.271) and good clinical outcome in both groups. The mean operation time was significantly longer in the CAD group (P < 0.001).

CONCLUSIONS

This study shows that the use of iAssist accelerometric CAD facilitates comparable good leg alignment after TKA in the frontal plane and more accurate tibial slope with fewer outliers in the sagittal plane compared with a conventional technique. Our operation time was longer with CAD.

New technology-based assistive techniques in total knee arthroplasty: A Bayesian network meta-analysis and systematic review

BACKGROUND

The radiological and clinical efficiency among robot-assisted surgery (RAS), computer-assisted navigation system (CAS) and conventional (CON) total knee arthroplasty (TKA) remains controversial.

METHODS

Bayesian network meta-analysis (NMA) and systematic review were performed to investigate radiological and clinical efficiency respectively. The certainty of the evidence was evaluated using GRADE and CERQual tool.

RESULTS

Thirty-four RCTs (7289 patients and 7424 knees) were included. The NMA showed that RAS-TKA had the highest probability for mechanical axis restoration (odds ratio for RAS vs. CAS 3.79, CrI 1.14 to 20.54, very low certainty), followed by CAS-TKA (odds ratio for CAS vs. CON 2.55, CrI 1.67 to 4.01, very low certainty) and then CON-TKA, without significant differences in other radiological parameters. No differences were found in clinical outcomes after qualitative systematic review (overall low certainty).

CONCLUSIONS

Technology-based assistive techniques (CAS and RAS) may surpass the CON-TKA, when considering higher radiological accuracy and comparable clinical outcomes. This article is protected by copyright. All rights reserved.

Population-based Survivorship of Computer-navigated Versus Conventional Total Knee Arthroplasty

BACKGROUND

The goal of computer navigation in total knee arthroplasty (TKA) is to improve the accuracy of alignment. However, the relationship between this technology and implant longevity has not been established. The purpose of this study was to analyze survivorship of computer-navigated TKAs compared with traditionally instrumented TKAs.

METHODS

The PearlDiver Medicare database was used to identify patients who underwent a primary TKA using conventional instrumentation versus computer navigation between 2005 and 2014. Conventional and computer-navigated cohorts were matched by age, sex, year of procedure, comorbidities, and geographic region. Kaplan-Meier curves were generated to estimate survivorship with aseptic mechanical complications, periprosthetic joint infection, and all-cause revision as end points.

RESULTS

During the study period, 75,709 patients who underwent a computer-navigated TKA were identified and matched to a cohort of 75,676 conventional TKA patients from a cohort of 1,607,803 conventional TKA patients. No difference existed in survival between conventional instrumentation (94.7%) and navigated TKAs (95.1%, P = 0.06) at 5 years. A modest decrease was found in revisions secondary to mechanical complications associated with navigation (96.1%) compared with conventional instrumentation (95.7%, P = 0.02) at 5 years. No differences in revision rates because of periprosthetic joint infection were observed (97.9% versus 97.9% event-free survival, P = 0.30). In a subgroup of Medicare patients younger than 65 years of age, use of computer navigation was associated with a decrease in all-cause revision (91.4% versus 89.6% event free survival, P = 0.01) and revision secondary to mechanical complications (89.6% versus 87.8% event-free survival, P = 0.01) at 5 years.

DISCUSSION

Among Medicare patients, no notable difference existed in TKA survival associated with the use of computer navigation at the 5-year follow-up. Use of computer navigation was associated with a slight decrease in revisions secondary to mechanical failure. Although improved survivorship was associated with patients younger than 65 years of age who had a navigated TKA, generalizability of these findings is limited given the unique characteristics of this Medicare subpopulation.

Computer and robotic - assisted total knee arthroplasty: a review of outcomes

Background

Total knee arthroplasty (TKA) is a successful treatment for tricompartmental knee arthritis. Computer navigation and robotic-assisted-surgery (RAS) have emerged as tools that aim to help plan and execute surgery with greater precision and consistency. We reviewed the most current literature to describe the historical background and outcomes compared to conventional TKA.

Methods

A review and synthesis of the literature comparing the patient reported outcomes (PROM’s) of RA TKA and computer-assisted (CA) TKA to conventional TKA was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

Results

CAS TKA improves accuracy and consistency of implant position, and appears to provide a small improvement in PROMs and implant survival compared to conventional TKA. RTKA similarly improves implant accuracy compared to conventional techniques and early results suggest a similar small benefit in PROMs compared to conventional TKA. A strengthening trend is emerging showing CAS TKA has greatest benefit to implant survival in people under 65. RTKA survival analysis data is more limited and early results do not allow strong conclusions, however early trends are similar to CAS TKA.

Conclusion

Results for CAS-TKA show improvement in alignment, and early clinical outcomes have revealed promising results, with longer-term data and medium-term survival analysis recently emerging showing small benefits over conventional TKA. RTKA represents another phase of development. Early results show similar trends to that of CAS TKA with longer-term data still to come.

Computerized Navigation: A Useful Tool in Total Knee Replacement

The purpose of computer assistance in a total knee replacement is to achieve optimal alignment, size, and positioning of the implant. The method is safe and accurate and may be particularly useful in cases with abnormal anatomy.

Are There Differences in Accuracy or Outcomes Scores Among Navigated, Robotic, Patient-specific Instruments or Standard Cutting Guides in TKA? A Network Meta-analysis

BACKGROUND

Several kinds of cutting guides, including patient-specific instrumentation, navigation, standard cutting guides, accelerometer-based navigation, and robotic guidance, are available to restore a planned alignment during TKA. No previous study has simultaneously compared all of these devices; a network meta-analysis is an especially appealing method because it allows comparisons across approaches that were not compared head-to-head in individual randomized controlled trials.

QUESTIONS/PURPOSES

We performed a network meta-analysis to determine whether novel approaches to achieving implant alignment, such as patient-specific instrumentation, navigation, accelerometer-based navigation, and robotic guidance, provide any advantage over standard cutting guides in terms of: (1) hip-knee-ankle (HKA) alignment outliers greater than ± 3°, (2) outcome scores (1989 - Knee Society Score and WOMAC score) measured 6 months after surgery, or (3) femoral and tibial implant malalignment (greater than ± 3°), taken separately, in the frontal and sagittal plane, as well as other secondary outcomes including validated outcome scores 1 and 2 years after surgery.

METHODS

In our network meta-analysis, we included randomized controlled trials comparing the different cutting guides by using at least one of the previously specified criteria, without limitation on language or date of publication. We searched electronic databases, major orthopaedic journals, proceedings of major orthopaedic meetings, ClinicalTrials.gov, and the World Health Organization's International Clinical Trials Registry Platform until October 1, 2018. This led to the inclusion of 90 randomized controlled trials involving 9389 patients (mean age 68.8 years) with 10,336 TKAs. Two reviewers independently selected trials and extracted data. The primary outcomes were the proportion patients with malalignment of the HKA angle (defined as HKA > 3° from neutral) and the Knee Society Score and WOMAC scores at 6 months postoperatively. We combined direct and indirect comparisons using a Bayesian network meta-analysis framework to assess and compare the effect of different cutting guides on outcomes. Bayesian estimates are based on the posterior distribution of an endpoint and are called credible intervals. Usually the 95% credible interval, corresponding to a posterior probability of 0.95 that the endpoint lies in the interval, is computed. Unlike the frequentist approach, the Bayesian approach does not allow the calculation of the p value.

RESULTS

The proportion of HKA outliers was lower with navigation than with patient-specific instrumentation (risk ratio 0.46 [95% credible interval (CI) 0.34 to 0.63]) and standard cutting guides (risk ratio 0.45 [95% CI 0.37 to 0.53]); however, this corresponded to an actual difference of only 12% of patients for navigation versus 21% of patients for patient-specific instrumentation, and 12% of patients for navigation versus 25% for standard cutting guides. We found no differences for other comparisons between different cutting guides, including robotics and the accelerometer. We found no differences in the Knee Society Score or WOMAC score between the different cutting guides at 6 months. Regarding secondary outcomes, navigation reduced the risk of frontal and sagittal malalignments for femoral and tibial components compared with the standard cutting guides, but none of the other cutting guides showed superiority for the other secondary outcomes.

CONCLUSIONS

Navigation resulted in approximately 10% fewer patients having HKA outliers of more than 3°, without any corresponding improvement in validated outcomes scores. It is unknown whether this incremental reduction in the proportion of patients who have alignment outside a window that itself has been called into question will justify the increased costs and surgical time associated with the approach. We believe that until or unless these new approaches either (1) convincingly demonstrate superior survivorship, or (2) convincingly demonstrate superior outcomes, surgeons and hospitals should not use these approaches since they add cost, have a learning curve (during which some patients may be harmed), and have the risks associated with uncertainty of novel surgical approaches.

LEVEL OF EVIDENCE

Level I, therapeutic study.

Comparison of intraoperative kinematics and their influence on the clinical outcomes between posterior stabilized total knee arthroplasty and bi-cruciate stabilized total knee arthroplasty

BACKGROUND

Of all the intraoperative kinematic parameters recorded using navigation systems, femorotibial rotational alignment is reportedly associated with the clinical outcomes of cruciate retaining and posterior stabilized (PS) total knee arthroplasty (TKA). However, to our knowledge, there are no reports on the relationship of newly designed bi-cruciate stabilized (BCS) TKA and intraoperative rotational kinematics. We aimed to clarify and compare the relationships between the intraoperative kinematics and clinical outcomes of BCS TKA and PS TKA.

METHODS

We compared the intraoperative rotational kinematics and clinical outcomes at two years postoperatively of 56 BCS TKA patients and 55 PS TKA patients. Further, we evaluated the relationship between the femorotibial rotational kinematics and clinical outcomes.

RESULTS

The maximum flexion angle and the pain subscale of the Knee injury and Osteoarthritis Outcome Score (KOOS) in BCS TKA were significantly better than those in PS TKA. The intraoperative kinematic data of BCS TKA showed "screw-home" movement, while that of PS TKA did not show this movement. The rotational angular differences between at maximum flexion angle and at 60° flexion of BCS TKA showed positive correlations with the improvement of KOOS pain, symptom, activity of daily living and sports subscales. The rotational angular differences between at maximum flexion angle and at 30° flexion in PS TKA showed positive correlations with the maximum flexion angle.

CONCLUSION

Intraoperative femorotibial rotational kinematics and its influence on the clinical outcomes were different between BCS and PS TKA. BCS TKA showed more normal-like kinematics and better clinical results than PS TKA.

Computer-Assisted Technologies in Arthroplasty: Navigating Your Way Today

Computer-assisted technologies that are used in arthroplasty include navigation, image-derived instrumentation (IDI), and robotics. Computer-assisted navigation improves accuracy and allows for real-time assessment of component positioning and soft-tissue tension. It is not clear whether the implementation of these technologies improves the clinical outcome of surgery. High cost and time demands have prevented the global implementation of computer-assisted technologies.

Clinical outcomes of two-stage total knee arthroplasty using articulating cement spacer in patients with infected arthritic knee: A comparison with arthroscopic surgery

BACKGROUND

The aim of this study was to compare the functional outcomes and recurrence rate of infection between patients who underwent arthroscopic surgery and two-stage total knee arthroplasty (TKA) for infected arthritic knees.

METHODS

A retrospective analysis was conducted on 52 patients (52 knees) with advanced knee joint arthritis who underwent arthroscopic surgery or two-stage TKA using articulating cement spacer (ACS) for knee joint infection between January 2009 and November 2013. Of the 52 patients (52 knees), 38 and 14 patients underwent arthroscopic surgery (AS group) and two-stage TKA using ACS (ACS-TKA group), respectively. Patient-reported outcomes (Knee Injury and Osteoarthritis Outcome Score (KOOS) and EuroQol-Visual Analog Scales (EQ-VAS)); range of motion; and recurrence rate of infection were evaluated.

RESULTS

Recurrence of infection was observed in 7/38 patients who underwent arthroscopic surgery, all of whom received two-stage TKA using ACS. Regarding the functional outcomes of the ACS-TKA group obtained before conversion to TKA and those of the AS group obtained six months after arthroscopic surgery, the former group had better outcomes for KOOS pain, KOOS activities of daily living, KOOS quality of life, and EQ-VAS. Regarding the functional outcomes of the ACS-TKA group obtained during the last follow-up and after conversion to TKA and those of the AS group who underwent TKA after arthroscopic surgery, no significant between-group differences were observed. The infection recurrence rate was higher in the AS than in the ACS-TKA group.

CONCLUSIONS

Considering infection control and functional outcomes, two-stage TKA using ACS can be an effective alternative treatment for patients with infected arthritic knees.